diff --git a/thyme.cabal b/thyme.cabal
index e12ee98..893de5f 100644
--- a/thyme.cabal
+++ b/thyme.cabal
@@ -103,7 +103,7 @@ library
         vector-space >= 0.8
     if os(windows)
         build-depends: Win32
-    if os(darwin)
+    if os(darwin) || os(freebsd)
         build-tools: cpphs
         ghc-options: -pgmP cpphs -optP--cpp
     if flag(lens) || flag(docs)